[PATCH V6 0/2] watchdog: mtk: support pre-timeout when the bark irq is available

[PATCH V6 0/2] watchdog: mtk: support pre-timeout when the bark irq is available

[Wang Qing]

Use the bark interrupt as the pretimeout notifier if available.
The pretimeout notification shall occur at timeout-sec/2.

Wang Qing (2):
  watchdog: mtk: support pre-timeout when the bark irq is available
  doc: mtk-wdt: support pre-timeout when the bark irq is available

 .../devicetree/bindings/watchdog/mtk-wdt.txt       |  3 ++
 drivers/watchdog/mtk_wdt.c                         | 53 ++++++++++++++++++++--
 2 files changed, 51 insertions(+), 5 deletions(-)

-- 
2.7.4

[PATCH V6 1/2] watchdog: mtk: support pre-timeout when the bark irq is available

[Wang Qing]

Use the bark interrupt as the pretimeout notifier if available.

When the watchdog timer expires in dual mode, an interrupt will be
triggered first, then the timing restarts. The reset signal will be
initiated when the timer expires again.

The pretimeout notification shall occur at timeout-sec/2.

V2:
- panic() by default if WATCHDOG_PRETIMEOUT_GOV is not enabled.

V3:
- Modify the pretimeout behavior, manually reset after the pretimeout
- is processed and wait until timeout.

V4:
- Remove pretimeout related processing. 
- Add dual mode control separately.

V5:
- Fix some formatting and printing problems.

V6:
- Realize pretimeout processing through dualmode.

Signed-off-by: Wang Qing <wangqing@vivo.com>
---
 drivers/watchdog/mtk_wdt.c | 53 +++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 48 insertions(+), 5 deletions(-)

diff --git a/drivers/watchdog/mtk_wdt.c b/drivers/watchdog/mtk_wdt.c
index 97ca993..ebc648b
--- a/drivers/watchdog/mtk_wdt.c
+++ b/drivers/watchdog/mtk_wdt.c
@@ -25,6 +25,7 @@
 #include <linux/reset-controller.h>
 #include <linux/types.h>
 #include <linux/watchdog.h>
+#include <linux/interrupt.h>
 
 #define WDT_MAX_TIMEOUT		31
 #define WDT_MIN_TIMEOUT		1
@@ -184,15 +185,22 @@ static int mtk_wdt_set_timeout(struct watchdog_device *wdt_dev,
 {
 	struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
 	void __iomem *wdt_base = mtk_wdt->wdt_base;
+	unsigned int timeout_interval;
 	u32 reg;
 
-	wdt_dev->timeout = timeout;
+	timeout_interval = wdt_dev->timeout = timeout;
+	/*
+	 * In dual mode, irq will be triggered at timeout/2
+	 * the real timeout occurs at timeout
+	 */
+	if (wdt_dev->pretimeout)
+		timeout_interval = wdt_dev->pretimeout = timeout/2;
 
 	/*
 	 * One bit is the value of 512 ticks
 	 * The clock has 32 KHz
 	 */
-	reg = WDT_LENGTH_TIMEOUT(timeout << 6) | WDT_LENGTH_KEY;
+	reg = WDT_LENGTH_TIMEOUT(timeout_interval << 6) | WDT_LENGTH_KEY;
 	iowrite32(reg, wdt_base + WDT_LENGTH);
 
 	mtk_wdt_ping(wdt_dev);
@@ -239,13 +247,25 @@ static int mtk_wdt_start(struct watchdog_device *wdt_dev)
 		return ret;
 
 	reg = ioread32(wdt_base + WDT_MODE);
-	reg &= ~(WDT_MODE_IRQ_EN | WDT_MODE_DUAL_EN);
+	if (wdt_dev->pretimeout)
+		reg |= (WDT_MODE_IRQ_EN | WDT_MODE_DUAL_EN);
+	else
+		reg &= ~(WDT_MODE_IRQ_EN | WDT_MODE_DUAL_EN);
 	reg |= (WDT_MODE_EN | WDT_MODE_KEY);
 	iowrite32(reg, wdt_base + WDT_MODE);
 
 	return 0;
 }
 
+static irqreturn_t mtk_wdt_isr(int irq, void *arg)
+{
+	struct watchdog_device *wdd = arg;
+
+	watchdog_notify_pretimeout(wdd);
+
+	return IRQ_HANDLED;
+}
+
 static const struct watchdog_info mtk_wdt_info = {
 	.identity	= DRV_NAME,
 	.options	= WDIOF_SETTIMEOUT |
@@ -253,6 +273,14 @@ static const struct watchdog_info mtk_wdt_info = {
 			  WDIOF_MAGICCLOSE,
 };
 
+static const struct watchdog_info mtk_wdt_pt_info = {
+	.identity	= DRV_NAME,
+	.options	= WDIOF_SETTIMEOUT |
+			  WDIOF_PRETIMEOUT |
+			  WDIOF_KEEPALIVEPING |
+			  WDIOF_MAGICCLOSE,
+};
+
 static const struct watchdog_ops mtk_wdt_ops = {
 	.owner		= THIS_MODULE,
 	.start		= mtk_wdt_start,
@@ -267,7 +295,7 @@ static int mtk_wdt_probe(struct platform_device *pdev)
 	struct device *dev = &pdev->dev;
 	struct mtk_wdt_dev *mtk_wdt;
 	const struct mtk_wdt_data *wdt_data;
-	int err;
+	int err, irq;
 
 	mtk_wdt = devm_kzalloc(dev, sizeof(*mtk_wdt), GFP_KERNEL);
 	if (!mtk_wdt)
@@ -279,7 +307,22 @@ static int mtk_wdt_probe(struct platform_device *pdev)
 	if (IS_ERR(mtk_wdt->wdt_base))
 		return PTR_ERR(mtk_wdt->wdt_base);
 
-	mtk_wdt->wdt_dev.info = &mtk_wdt_info;
+	irq = platform_get_irq(pdev, 0);
+	if (irq > 0) {
+		err = devm_request_irq(&pdev->dev, irq, mtk_wdt_isr, 0, "wdt_bark",
+							&mtk_wdt->wdt_dev);
+		if (err)
+			return err;
+
+		mtk_wdt->wdt_dev.info = &mtk_wdt_pt_info;
+		mtk_wdt->wdt_dev.pretimeout = WDT_MAX_TIMEOUT/2;
+	} else {
+		if (irq == -EPROBE_DEFER)
+			return -EPROBE_DEFER;
+
+		mtk_wdt->wdt_dev.info = &mtk_wdt_info;
+	}
+
 	mtk_wdt->wdt_dev.ops = &mtk_wdt_ops;
 	mtk_wdt->wdt_dev.timeout = WDT_MAX_TIMEOUT;
 	mtk_wdt->wdt_dev.max_hw_heartbeat_ms = WDT_MAX_TIMEOUT * 1000;
-- 
2.7.4

Re: [PATCH V6 1/2] watchdog: mtk: support pre-timeout when the bark irq is available

[Guenter Roeck]

On 4/21/21 7:45 PM, Wang Qing wrote:
> Use the bark interrupt as the pretimeout notifier if available.
> 
> When the watchdog timer expires in dual mode, an interrupt will be
> triggered first, then the timing restarts. The reset signal will be
> initiated when the timer expires again.
> 
> The pretimeout notification shall occur at timeout-sec/2.
> 
> V2:
> - panic() by default if WATCHDOG_PRETIMEOUT_GOV is not enabled.
> 
> V3:
> - Modify the pretimeout behavior, manually reset after the pretimeout
> - is processed and wait until timeout.
> 
> V4:
> - Remove pretimeout related processing. 
> - Add dual mode control separately.
> 
> V5:
> - Fix some formatting and printing problems.
> 
> V6:
> - Realize pretimeout processing through dualmode.
> 
> Signed-off-by: Wang Qing <wangqing@vivo.com>
> ---
>  drivers/watchdog/mtk_wdt.c | 53 +++++++++++++++++++++++++++++++++++++++++-----
>  1 file changed, 48 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/watchdog/mtk_wdt.c b/drivers/watchdog/mtk_wdt.c
> index 97ca993..ebc648b
> --- a/drivers/watchdog/mtk_wdt.c
> +++ b/drivers/watchdog/mtk_wdt.c
> @@ -25,6 +25,7 @@
>  #include <linux/reset-controller.h>
>  #include <linux/types.h>
>  #include <linux/watchdog.h>
> +#include <linux/interrupt.h>
>  
>  #define WDT_MAX_TIMEOUT		31
>  #define WDT_MIN_TIMEOUT		1
> @@ -184,15 +185,22 @@ static int mtk_wdt_set_timeout(struct watchdog_device *wdt_dev,
>  {
>  	struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
>  	void __iomem *wdt_base = mtk_wdt->wdt_base;
> +	unsigned int timeout_interval;
>  	u32 reg;
>  
> -	wdt_dev->timeout = timeout;
> +	timeout_interval = wdt_dev->timeout = timeout;
> +	/*
> +	 * In dual mode, irq will be triggered at timeout/2
> +	 * the real timeout occurs at timeout
> +	 */
> +	if (wdt_dev->pretimeout)
> +		timeout_interval = wdt_dev->pretimeout = timeout/2;

Please run checkpatch --strict and fix what it reports.
Also, there should be a set_pretimeout function to set the
pretimeout. It is ok to update it here, but it should be set
in its own function to make sure that the actual value
is reported back to userspace.

Thanks,
Guenter

>  
>  	/*
>  	 * One bit is the value of 512 ticks
>  	 * The clock has 32 KHz
>  	 */
> -	reg = WDT_LENGTH_TIMEOUT(timeout << 6) | WDT_LENGTH_KEY;
> +	reg = WDT_LENGTH_TIMEOUT(timeout_interval << 6) | WDT_LENGTH_KEY;
>  	iowrite32(reg, wdt_base + WDT_LENGTH);
>  
>  	mtk_wdt_ping(wdt_dev);
> @@ -239,13 +247,25 @@ static int mtk_wdt_start(struct watchdog_device *wdt_dev)
>  		return ret;
>  
>  	reg = ioread32(wdt_base + WDT_MODE);
> -	reg &= ~(WDT_MODE_IRQ_EN | WDT_MODE_DUAL_EN);
> +	if (wdt_dev->pretimeout)
> +		reg |= (WDT_MODE_IRQ_EN | WDT_MODE_DUAL_EN);
> +	else
> +		reg &= ~(WDT_MODE_IRQ_EN | WDT_MODE_DUAL_EN);
>  	reg |= (WDT_MODE_EN | WDT_MODE_KEY);
>  	iowrite32(reg, wdt_base + WDT_MODE);
>  
>  	return 0;
>  }
>  
> +static irqreturn_t mtk_wdt_isr(int irq, void *arg)
> +{
> +	struct watchdog_device *wdd = arg;
> +
> +	watchdog_notify_pretimeout(wdd);
> +
> +	return IRQ_HANDLED;
> +}
> +
>  static const struct watchdog_info mtk_wdt_info = {
>  	.identity	= DRV_NAME,
>  	.options	= WDIOF_SETTIMEOUT |
> @@ -253,6 +273,14 @@ static const struct watchdog_info mtk_wdt_info = {
>  			  WDIOF_MAGICCLOSE,
>  };
>  
> +static const struct watchdog_info mtk_wdt_pt_info = {
> +	.identity	= DRV_NAME,
> +	.options	= WDIOF_SETTIMEOUT |
> +			  WDIOF_PRETIMEOUT |
> +			  WDIOF_KEEPALIVEPING |
> +			  WDIOF_MAGICCLOSE,
> +};
> +
>  static const struct watchdog_ops mtk_wdt_ops = {
>  	.owner		= THIS_MODULE,
>  	.start		= mtk_wdt_start,
> @@ -267,7 +295,7 @@ static int mtk_wdt_probe(struct platform_device *pdev)
>  	struct device *dev = &pdev->dev;
>  	struct mtk_wdt_dev *mtk_wdt;
>  	const struct mtk_wdt_data *wdt_data;
> -	int err;
> +	int err, irq;
>  
>  	mtk_wdt = devm_kzalloc(dev, sizeof(*mtk_wdt), GFP_KERNEL);
>  	if (!mtk_wdt)
> @@ -279,7 +307,22 @@ static int mtk_wdt_probe(struct platform_device *pdev)
>  	if (IS_ERR(mtk_wdt->wdt_base))
>  		return PTR_ERR(mtk_wdt->wdt_base);
>  
> -	mtk_wdt->wdt_dev.info = &mtk_wdt_info;
> +	irq = platform_get_irq(pdev, 0);
> +	if (irq > 0) {
> +		err = devm_request_irq(&pdev->dev, irq, mtk_wdt_isr, 0, "wdt_bark",
> +							&mtk_wdt->wdt_dev);
> +		if (err)
> +			return err;
> +
> +		mtk_wdt->wdt_dev.info = &mtk_wdt_pt_info;
> +		mtk_wdt->wdt_dev.pretimeout = WDT_MAX_TIMEOUT/2;
> +	} else {
> +		if (irq == -EPROBE_DEFER)
> +			return -EPROBE_DEFER;
> +
> +		mtk_wdt->wdt_dev.info = &mtk_wdt_info;
> +	}
> +
>  	mtk_wdt->wdt_dev.ops = &mtk_wdt_ops;
>  	mtk_wdt->wdt_dev.timeout = WDT_MAX_TIMEOUT;
>  	mtk_wdt->wdt_dev.max_hw_heartbeat_ms = WDT_MAX_TIMEOUT * 1000;
> 

Re:Re: [PATCH V6 1/2] watchdog: mtk: support pre-timeout when the bark irq is available

[王擎]

>On 4/21/21 7:45 PM, Wang Qing wrote:
>> Use the bark interrupt as the pretimeout notifier if available.
>> 
>> When the watchdog timer expires in dual mode, an interrupt will be
>> triggered first, then the timing restarts. The reset signal will be
>> initiated when the timer expires again.
>> 
>> The pretimeout notification shall occur at timeout-sec/2.
>> 
>> V2:
>> - panic() by default if WATCHDOG_PRETIMEOUT_GOV is not enabled.
>> 
>> V3:
>> - Modify the pretimeout behavior, manually reset after the pretimeout
>> - is processed and wait until timeout.
>> 
>> V4:
>> - Remove pretimeout related processing. 
>> - Add dual mode control separately.
>> 
>> V5:
>> - Fix some formatting and printing problems.
>> 
>> V6:
>> - Realize pretimeout processing through dualmode.
>> 
>> Signed-off-by: Wang Qing <wangqing@vivo.com>
>> ---
>>  drivers/watchdog/mtk_wdt.c | 53 +++++++++++++++++++++++++++++++++++++++++-----
>>  1 file changed, 48 insertions(+), 5 deletions(-)
>> 
>> diff --git a/drivers/watchdog/mtk_wdt.c b/drivers/watchdog/mtk_wdt.c
>> index 97ca993..ebc648b
>> --- a/drivers/watchdog/mtk_wdt.c
>> +++ b/drivers/watchdog/mtk_wdt.c
>> @@ -25,6 +25,7 @@
>>  #include <linux/reset-controller.h>
>>  #include <linux/types.h>
>>  #include <linux/watchdog.h>
>> +#include <linux/interrupt.h>
>>  
>>  #define WDT_MAX_TIMEOUT		31
>>  #define WDT_MIN_TIMEOUT		1
>> @@ -184,15 +185,22 @@ static int mtk_wdt_set_timeout(struct watchdog_device *wdt_dev,
>>  {
>>  	struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
>>  	void __iomem *wdt_base = mtk_wdt->wdt_base;
>> +	unsigned int timeout_interval;
>>  	u32 reg;
>>  
>> -	wdt_dev->timeout = timeout;
>> +	timeout_interval = wdt_dev->timeout = timeout;
>> +	/*
>> +	 * In dual mode, irq will be triggered at timeout/2
>> +	 * the real timeout occurs at timeout
>> +	 */
>> +	if (wdt_dev->pretimeout)
>> +		timeout_interval = wdt_dev->pretimeout = timeout/2;
>
>Please run checkpatch --strict and fix what it reports.
>Also, there should be a set_pretimeout function to set the
>pretimeout. It is ok to update it here, but it should be set
>in its own function to make sure that the actual value
>is reported back to userspace.
>
>Thanks,
>Guenter

The reason why the set_pretimeout interface is not provided is 
because the pretimeout is fixed after the timeout is set,  we need
to modify timeout after setting pretimeout, which is puzzling.

I will point out this behavior in the doc and comments,
or implement the set_pretimeout interface only as a print prompt.
What do you think of it?

Thanks,
Qing
>
>>  
>>  	/*
>>  	 * One bit is the value of 512 ticks
>>  	 * The clock has 32 KHz
>>  	 */
>> -	reg = WDT_LENGTH_TIMEOUT(timeout << 6) | WDT_LENGTH_KEY;
>> +	reg = WDT_LENGTH_TIMEOUT(timeout_interval << 6) | WDT_LENGTH_KEY;
>>  	iowrite32(reg, wdt_base + WDT_LENGTH);
>>  
>>  	mtk_wdt_ping(wdt_dev);
>> @@ -239,13 +247,25 @@ static int mtk_wdt_start(struct watchdog_device *wdt_dev)
>>  		return ret;
>>  
>>  	reg = ioread32(wdt_base + WDT_MODE);
>> -	reg &= ~(WDT_MODE_IRQ_EN | WDT_MODE_DUAL_EN);
>> +	if (wdt_dev->pretimeout)
>> +		reg |= (WDT_MODE_IRQ_EN | WDT_MODE_DUAL_EN);
>> +	else
>> +		reg &= ~(WDT_MODE_IRQ_EN | WDT_MODE_DUAL_EN);
>>  	reg |= (WDT_MODE_EN | WDT_MODE_KEY);
>>  	iowrite32(reg, wdt_base + WDT_MODE);
>>  
>>  	return 0;
>>  }
>>  
>> +static irqreturn_t mtk_wdt_isr(int irq, void *arg)
>> +{
>> +	struct watchdog_device *wdd = arg;
>> +
>> +	watchdog_notify_pretimeout(wdd);
>> +
>> +	return IRQ_HANDLED;
>> +}
>> +
>>  static const struct watchdog_info mtk_wdt_info = {
>>  	.identity	= DRV_NAME,
>>  	.options	= WDIOF_SETTIMEOUT |
>> @@ -253,6 +273,14 @@ static const struct watchdog_info mtk_wdt_info = {
>>  			  WDIOF_MAGICCLOSE,
>>  };
>>  
>> +static const struct watchdog_info mtk_wdt_pt_info = {
>> +	.identity	= DRV_NAME,
>> +	.options	= WDIOF_SETTIMEOUT |
>> +			  WDIOF_PRETIMEOUT |
>> +			  WDIOF_KEEPALIVEPING |
>> +			  WDIOF_MAGICCLOSE,
>> +};
>> +
>>  static const struct watchdog_ops mtk_wdt_ops = {
>>  	.owner		= THIS_MODULE,
>>  	.start		= mtk_wdt_start,
>> @@ -267,7 +295,7 @@ static int mtk_wdt_probe(struct platform_device *pdev)
>>  	struct device *dev = &pdev->dev;
>>  	struct mtk_wdt_dev *mtk_wdt;
>>  	const struct mtk_wdt_data *wdt_data;
>> -	int err;
>> +	int err, irq;
>>  
>>  	mtk_wdt = devm_kzalloc(dev, sizeof(*mtk_wdt), GFP_KERNEL);
>>  	if (!mtk_wdt)
>> @@ -279,7 +307,22 @@ static int mtk_wdt_probe(struct platform_device *pdev)
>>  	if (IS_ERR(mtk_wdt->wdt_base))
>>  		return PTR_ERR(mtk_wdt->wdt_base);
>>  
>> -	mtk_wdt->wdt_dev.info = &mtk_wdt_info;
>> +	irq = platform_get_irq(pdev, 0);
>> +	if (irq > 0) {
>> +		err = devm_request_irq(&pdev->dev, irq, mtk_wdt_isr, 0, "wdt_bark",
>> +							&mtk_wdt->wdt_dev);
>> +		if (err)
>> +			return err;
>> +
>> +		mtk_wdt->wdt_dev.info = &mtk_wdt_pt_info;
>> +		mtk_wdt->wdt_dev.pretimeout = WDT_MAX_TIMEOUT/2;
>> +	} else {
>> +		if (irq == -EPROBE_DEFER)
>> +			return -EPROBE_DEFER;
>> +
>> +		mtk_wdt->wdt_dev.info = &mtk_wdt_info;
>> +	}
>> +
>>  	mtk_wdt->wdt_dev.ops = &mtk_wdt_ops;
>>  	mtk_wdt->wdt_dev.timeout = WDT_MAX_TIMEOUT;
>>  	mtk_wdt->wdt_dev.max_hw_heartbeat_ms = WDT_MAX_TIMEOUT * 1000;
>> 
>

Re: [PATCH V6 1/2] watchdog: mtk: support pre-timeout when the bark irq is available

[Guenter Roeck]

On 4/21/21 8:46 PM, 王擎 wrote:
> 
>> On 4/21/21 7:45 PM, Wang Qing wrote:
>>> Use the bark interrupt as the pretimeout notifier if available.
>>>
>>> When the watchdog timer expires in dual mode, an interrupt will be
>>> triggered first, then the timing restarts. The reset signal will be
>>> initiated when the timer expires again.
>>>
>>> The pretimeout notification shall occur at timeout-sec/2.
>>>
>>> V2:
>>> - panic() by default if WATCHDOG_PRETIMEOUT_GOV is not enabled.
>>>
>>> V3:
>>> - Modify the pretimeout behavior, manually reset after the pretimeout
>>> - is processed and wait until timeout.
>>>
>>> V4:
>>> - Remove pretimeout related processing. 
>>> - Add dual mode control separately.
>>>
>>> V5:
>>> - Fix some formatting and printing problems.
>>>
>>> V6:
>>> - Realize pretimeout processing through dualmode.
>>>
>>> Signed-off-by: Wang Qing <wangqing@vivo.com>
>>> ---
>>>  drivers/watchdog/mtk_wdt.c | 53 +++++++++++++++++++++++++++++++++++++++++-----
>>>  1 file changed, 48 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/drivers/watchdog/mtk_wdt.c b/drivers/watchdog/mtk_wdt.c
>>> index 97ca993..ebc648b
>>> --- a/drivers/watchdog/mtk_wdt.c
>>> +++ b/drivers/watchdog/mtk_wdt.c
>>> @@ -25,6 +25,7 @@
>>>  #include <linux/reset-controller.h>
>>>  #include <linux/types.h>
>>>  #include <linux/watchdog.h>
>>> +#include <linux/interrupt.h>
>>>  
>>>  #define WDT_MAX_TIMEOUT		31
>>>  #define WDT_MIN_TIMEOUT		1
>>> @@ -184,15 +185,22 @@ static int mtk_wdt_set_timeout(struct watchdog_device *wdt_dev,
>>>  {
>>>  	struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
>>>  	void __iomem *wdt_base = mtk_wdt->wdt_base;
>>> +	unsigned int timeout_interval;
>>>  	u32 reg;
>>>  
>>> -	wdt_dev->timeout = timeout;
>>> +	timeout_interval = wdt_dev->timeout = timeout;
>>> +	/*
>>> +	 * In dual mode, irq will be triggered at timeout/2
>>> +	 * the real timeout occurs at timeout
>>> +	 */
>>> +	if (wdt_dev->pretimeout)
>>> +		timeout_interval = wdt_dev->pretimeout = timeout/2;
>>
>> Please run checkpatch --strict and fix what it reports.
>> Also, there should be a set_pretimeout function to set the
>> pretimeout. It is ok to update it here, but it should be set
>> in its own function to make sure that the actual value
>> is reported back to userspace.
>>
>> Thanks,
>> Guenter
> 
> The reason why the set_pretimeout interface is not provided is 
> because the pretimeout is fixed after the timeout is set,  we need
> to modify timeout after setting pretimeout, which is puzzling.
> 

What you need to do is to set pretimeout = timeout / 2 if a pretimeout
is set to a value != 0. Just like we adjust timeout to valid values
when set, we adjust pretimeout as well. I don't see a problem with that.

Guenter

Re:Re: [PATCH V6 1/2] watchdog: mtk: support pre-timeout when the bark irq is available

[王擎]

>On 4/21/21 8:46 PM, 王擎 wrote:
>> 
>>> On 4/21/21 7:45 PM, Wang Qing wrote:
>>>> Use the bark interrupt as the pretimeout notifier if available.
>>>>
>>>> When the watchdog timer expires in dual mode, an interrupt will be
>>>> triggered first, then the timing restarts. The reset signal will be
>>>> initiated when the timer expires again.
>>>>
>>>> The pretimeout notification shall occur at timeout-sec/2.
>>>>
>>>> V2:
>>>> - panic() by default if WATCHDOG_PRETIMEOUT_GOV is not enabled.
>>>>
>>>> V3:
>>>> - Modify the pretimeout behavior, manually reset after the pretimeout
>>>> - is processed and wait until timeout.
>>>>
>>>> V4:
>>>> - Remove pretimeout related processing. 
>>>> - Add dual mode control separately.
>>>>
>>>> V5:
>>>> - Fix some formatting and printing problems.
>>>>
>>>> V6:
>>>> - Realize pretimeout processing through dualmode.
>>>>
>>>> Signed-off-by: Wang Qing <wangqing@vivo.com>
>>>> ---
>>>>  drivers/watchdog/mtk_wdt.c | 53 +++++++++++++++++++++++++++++++++++++++++-----
>>>>  1 file changed, 48 insertions(+), 5 deletions(-)
>>>>
>>>> diff --git a/drivers/watchdog/mtk_wdt.c b/drivers/watchdog/mtk_wdt.c
>>>> index 97ca993..ebc648b
>>>> --- a/drivers/watchdog/mtk_wdt.c
>>>> +++ b/drivers/watchdog/mtk_wdt.c
>>>> @@ -25,6 +25,7 @@
>>>>  #include <linux/reset-controller.h>
>>>>  #include <linux/types.h>
>>>>  #include <linux/watchdog.h>
>>>> +#include <linux/interrupt.h>
>>>>  
>>>>  #define WDT_MAX_TIMEOUT		31
>>>>  #define WDT_MIN_TIMEOUT		1
>>>> @@ -184,15 +185,22 @@ static int mtk_wdt_set_timeout(struct watchdog_device *wdt_dev,
>>>>  {
>>>>  	struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
>>>>  	void __iomem *wdt_base = mtk_wdt->wdt_base;
>>>> +	unsigned int timeout_interval;
>>>>  	u32 reg;
>>>>  
>>>> -	wdt_dev->timeout = timeout;
>>>> +	timeout_interval = wdt_dev->timeout = timeout;
>>>> +	/*
>>>> +	 * In dual mode, irq will be triggered at timeout/2
>>>> +	 * the real timeout occurs at timeout
>>>> +	 */
>>>> +	if (wdt_dev->pretimeout)
>>>> +		timeout_interval = wdt_dev->pretimeout = timeout/2;
>>>
>>> Please run checkpatch --strict and fix what it reports.
>>> Also, there should be a set_pretimeout function to set the
>>> pretimeout. It is ok to update it here, but it should be set
>>> in its own function to make sure that the actual value
>>> is reported back to userspace.
>>>
>>> Thanks,
>>> Guenter
>> 
>> The reason why the set_pretimeout interface is not provided is 
>> because the pretimeout is fixed after the timeout is set,  we need
>> to modify timeout after setting pretimeout, which is puzzling.
>> 
>
>What you need to do is to set pretimeout = timeout / 2 if a pretimeout
>is set to a value != 0. Just like we adjust timeout to valid values
>when set, we adjust pretimeout as well. I don't see a problem with that.
>
>Guenter

Thanks, Guenter. But this will complicate the situation:
First, set_pretimeout will become an interface for dynamically enable and
disable the pre-timeout func, instead of adjusting the pretimeout time. 

Secondly, when the irq is not registered, the user cannot be allowed to set
the pretimeout to non-zero. When irq is registered, it doesn't make any sense
to turn off pre-timeout func. 

Because of the particularity of dual mode, I still insist on enabling the
pretimeout or not through devicetree. And looking forward to your suggestions.

Thanks,
Qing

Re: [PATCH V6 1/2] watchdog: mtk: support pre-timeout when the bark irq is available

[Guenter Roeck]

On 4/22/21 12:05 AM, 王擎 wrote:
> 
>> On 4/21/21 8:46 PM, 王擎 wrote:
>>>
>>>> On 4/21/21 7:45 PM, Wang Qing wrote:
>>>>> Use the bark interrupt as the pretimeout notifier if available.
>>>>>
>>>>> When the watchdog timer expires in dual mode, an interrupt will be
>>>>> triggered first, then the timing restarts. The reset signal will be
>>>>> initiated when the timer expires again.
>>>>>
>>>>> The pretimeout notification shall occur at timeout-sec/2.
>>>>>
>>>>> V2:
>>>>> - panic() by default if WATCHDOG_PRETIMEOUT_GOV is not enabled.
>>>>>
>>>>> V3:
>>>>> - Modify the pretimeout behavior, manually reset after the pretimeout
>>>>> - is processed and wait until timeout.
>>>>>
>>>>> V4:
>>>>> - Remove pretimeout related processing. 
>>>>> - Add dual mode control separately.
>>>>>
>>>>> V5:
>>>>> - Fix some formatting and printing problems.
>>>>>
>>>>> V6:
>>>>> - Realize pretimeout processing through dualmode.
>>>>>
>>>>> Signed-off-by: Wang Qing <wangqing@vivo.com>
>>>>> ---
>>>>>  drivers/watchdog/mtk_wdt.c | 53 +++++++++++++++++++++++++++++++++++++++++-----
>>>>>  1 file changed, 48 insertions(+), 5 deletions(-)
>>>>>
>>>>> diff --git a/drivers/watchdog/mtk_wdt.c b/drivers/watchdog/mtk_wdt.c
>>>>> index 97ca993..ebc648b
>>>>> --- a/drivers/watchdog/mtk_wdt.c
>>>>> +++ b/drivers/watchdog/mtk_wdt.c
>>>>> @@ -25,6 +25,7 @@
>>>>>  #include <linux/reset-controller.h>
>>>>>  #include <linux/types.h>
>>>>>  #include <linux/watchdog.h>
>>>>> +#include <linux/interrupt.h>
>>>>>  
>>>>>  #define WDT_MAX_TIMEOUT		31
>>>>>  #define WDT_MIN_TIMEOUT		1
>>>>> @@ -184,15 +185,22 @@ static int mtk_wdt_set_timeout(struct watchdog_device *wdt_dev,
>>>>>  {
>>>>>  	struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
>>>>>  	void __iomem *wdt_base = mtk_wdt->wdt_base;
>>>>> +	unsigned int timeout_interval;
>>>>>  	u32 reg;
>>>>>  
>>>>> -	wdt_dev->timeout = timeout;
>>>>> +	timeout_interval = wdt_dev->timeout = timeout;
>>>>> +	/*
>>>>> +	 * In dual mode, irq will be triggered at timeout/2
>>>>> +	 * the real timeout occurs at timeout
>>>>> +	 */
>>>>> +	if (wdt_dev->pretimeout)
>>>>> +		timeout_interval = wdt_dev->pretimeout = timeout/2;
>>>>
>>>> Please run checkpatch --strict and fix what it reports.
>>>> Also, there should be a set_pretimeout function to set the
>>>> pretimeout. It is ok to update it here, but it should be set
>>>> in its own function to make sure that the actual value
>>>> is reported back to userspace.
>>>>
>>>> Thanks,
>>>> Guenter
>>>
>>> The reason why the set_pretimeout interface is not provided is 
>>> because the pretimeout is fixed after the timeout is set,  we need
>>> to modify timeout after setting pretimeout, which is puzzling.
>>>
>>
>> What you need to do is to set pretimeout = timeout / 2 if a pretimeout
>> is set to a value != 0. Just like we adjust timeout to valid values
>> when set, we adjust pretimeout as well. I don't see a problem with that.
>>
>> Guenter
> 
> Thanks, Guenter. But this will complicate the situation:
> First, set_pretimeout will become an interface for dynamically enable and
> disable the pre-timeout func, instead of adjusting the pretimeout time. 
> 
Effectively yes. That is what it is, based on its limitations. That is
not a problem, and in true for every pretimeout function. Set it to 0,
and it is turned off. Set it to a value other than 0, and it is turned on.

> Secondly, when the irq is not registered, the user cannot be allowed to set
> the pretimeout to non-zero. When irq is registered, it doesn't make any sense
> to turn off pre-timeout func. 
> 

That is your opinion. It is still a user decision to turn it on or off,
just like it is a user decision to set the timeout to a specific value
or to enable the watchdog in the first place. There is no reason to
make it mandatory just because an interrupt has been provided
(or, rather, connected).

Also, if the interrupt is not provided, WDIOF_PRETIMEOUT is not set,
and trying to set the pretimeout would return -EOPNOTSUPP.

Guenter

[PATCH V6 2/2] doc: mtk-wdt: support pre-timeout when the bark irq is available

[Wang Qing]

Add description of pre-timeout in mtk-wdt.

Signed-off-by: Wang Qing <wangqing@vivo.com>
---
 Documentation/devicetree/bindings/watchdog/mtk-wdt.txt | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Documentation/devicetree/bindings/watchdog/mtk-wdt.txt b/Documentation/devicetree/bindings/watchdog/mtk-wdt.txt
index e36ba60..ae57d6c
--- a/Documentation/devicetree/bindings/watchdog/mtk-wdt.txt
+++ b/Documentation/devicetree/bindings/watchdog/mtk-wdt.txt
@@ -1,5 +1,8 @@
 Mediatek SoCs Watchdog timer
 
+The watchdog supports a pre-timeout interrupt that fires timeout-sec/2
+before the expiry.
+
 Required properties:
 
 - compatible should contain:
-- 
2.7.4

Re: [PATCH V6 2/2] doc: mtk-wdt: support pre-timeout when the bark irq is available

[Guenter Roeck]

On 4/21/21 7:45 PM, Wang Qing wrote:
> Add description of pre-timeout in mtk-wdt.
> 
> Signed-off-by: Wang Qing <wangqing@vivo.com>
> ---
>  Documentation/devicetree/bindings/watchdog/mtk-wdt.txt | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/watchdog/mtk-wdt.txt b/Documentation/devicetree/bindings/watchdog/mtk-wdt.txt
> index e36ba60..ae57d6c
> --- a/Documentation/devicetree/bindings/watchdog/mtk-wdt.txt
> +++ b/Documentation/devicetree/bindings/watchdog/mtk-wdt.txt
> @@ -1,5 +1,8 @@
>  Mediatek SoCs Watchdog timer
>  
> +The watchdog supports a pre-timeout interrupt that fires timeout-sec/2
> +before the expiry.
> +

Seems to me the interrupt should be listed as optional property.

Guenter

>  Required properties:
>  
>  - compatible should contain:
>